Effects of Mexiletine on Colonic Transit in a Patient With Irritable Bowel Syndrome - Constipation (IBS-C)

Effects of Mexiletine on Colonic Transit in a Patient With a Known SCN5A A997T Mutation

Status

Completed

Phases

Phase 1

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT01717404

Enrollment

Registered

2012-10-30

Start date

2012-10-31

Completion date

2012-11-30

Last updated

2013-10-01

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

IBS

Keywords

IBS

Brief summary

To understand if Mexiletine will restores normal colonic motility in a patient with irritable bowel syndrome - constipation (IBS-C) and a genetic mutation in SCN5A.

Detailed description

To understand if Mexiletine will restore normal colonic motility in a patient with a missense mutation in SCN5A, which encodes a voltage-sensitive sodium channel NaV1.5 as it is known to rescue certain expression defects of NaV1.5 in vitro.

Interventions

DRUGMexiletine

6-day treatment period during which the medication will be taken orally with an initial dose of: 200 mg every 8 hours for 3 doses on day 3, increasing to 300 mg every 8 hours on days 4 and 5 (6 doses), and increasing further to 400 mg every 8 hours on days 6-8 if no telemetry changes and no dose limiting side effects

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

FEMALE

Age

60 Years to 70 Years

Healthy volunteers

Inclusion criteria

* Established IBS diagnosis with a known A997T mutation in NaV1.5T

Exclusion criteria

* Normal 48-hour baseline transit study * Current use of mexiletine * Inability to stay in Rochester for 9 days for testing * Known allergy to mexiletine * Inability to complete daily diary * Taking a medication known to affect myotonia, had a coexisting neuromuscular disease, or had another serious medical illness including second- or third-degree heart block, atrial flutter, atrial fibrillation, ventricular arrhythmia, history of cardiac arrhythmia requiring medication, congestive heart failure, symptomatic cardiomyopathy, or symptomatic coronary artery disease * Inability to withdraw medications known to interact with mexiletine. Patient is currently not on any of these medications

Design outcomes

Primary

Measure	Time frame	Description
change in the 48 hour Colon Transit	Baseline to 10 days	Colon transit will be measured using validated scintigraphy methods conducted in our Clinical Research Unit (CRU).\[17, 18\] The participant will ingest a Tc-99m labeled sulfur colloid in egg to be used as a stomach marker and ln-111 chloride bound to activated charcoal enclosed in a methacrylate-coated capsule to measure colonic transit.

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026